|SIMMONS, G.W.H. - Delft University Of Technology|
|BASTIAANSSEN, W.G.M. - Delft University Of Technology|
|NGO, L.A. - Collaborator|
|HAIN, C. - University Of Maryland|
|SENAY, G.B. - Us Geological Survey (USGS)|
Submitted to: Remote Sensing
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/21/2016
Publication Date: 5/28/2016
Citation: Simmons, G., Bastiaanssen, W., Ngo, L., Hain, C., Anderson, M.C., Senay, G. 2016. Integrating global satellite-derived data products as a pre-analysis for hydrological modelling studies: a case study for the Red River Basin. Remote Sensing. https://doi.org/10.3390/rs8040279.
Interpretive Summary: Global surface and ground water resources are under increasing pressure from human water use and climate change. Well-informed decision making on water management is essential for coping with tensions between water availability and water demand. This requires a feasible methodology for quantifying the current state of water resources in terms of hydrological flows and connectivity, as well as indicators of water use and reuse. Once reasonable estimates of these quantities have been established, simulation models can be used to examine the predicted consequences of different scenarios related to policy adjustments, climate change, and land use modifications. This paper explores the use of multiple global satellite remote sensing products describing rainfall and evapotranspiration to describe major water balance components over the Red River Basin in China and Vietnam. Use of an ensemble of products minimizes sensitivity to modeling error associated with any given modeling technique. The ensemble products provided water balance estimates that were in good agreement with streamflow estimates, demonstrating the satellite products are reasonable at the basin scale. Once verified, the products are used to study annual water use by different land-use classes within the basin, as well as irrigated versus rainfed crop water use. Runoff response patterns and sub-surface moisture storage changes were also investigated at basin scale. The methods developed in this paper can be readily applied in other global basins, providing new tools for evaluating water use and water productivity at global scales.
Technical Abstract: With changes in weather patterns and intensifying anthropogenic water use, there is an increasing need for spatio-temporal information on water fluxes and stocks in river basins. The assortment of satellite-derived open-access information sources on rainfall (P) and land use / land cover (LULC) is currently being expanded with the application of actual evapotranspiration (ETact) algorithms on the global scale. We demonstrate how global remotely sensed P and ETact datasets can be merged to examine hydrological processes such as storage changes and streamflow prior to applying a numerical simulation model. The study area is the Red River Basin in China and Vietnam, a generally challenging basin for remotely sensed information due to frequent cloud cover. Over this region, several satellite-based P and ETact products are compared, and performance is evaluated using rain gauge records and longer-term averaged streamflow. A method is presented for fusing multiple satellite-derived ETact estimates to generate an ensemble product that may be less susceptible, on a global basis, to errors in individual modeling approaches. Subsequently, monthly satellite-derived rainfall and ETact are combined to assess the water balance for individual subcatchments and types of land use, defined using a global land use classification improved based on auxiliary satellite data. It was found that a combination of Terrestrial Rainfall Mapping Mission (TRMM) rainfall and the ensemble Etact product is consistent with streamflow records in both space and time. It is concluded that monthly storage changes, multi-annual streamflow and water yield per LULC type in the Red River Basin can be successfully assessed based on currently available global satellite-derived products.